Outcome measures in Sjögren's disease

In this thesis, ‘Outcome measures in Sjögren’s disease’, we researched outcome measures which are used to measure treatment effect in clinical trials in Sjögren’s disease. Sjögren’s disease is a systemic autoimmune disease, which means that the immune system attacks cells of its own body. In Sjögren’s disease this leads to inflammation of tear and salivary glands. The disease is characterized by dryness complaints of eyes and mouth, fatigue and arthralgia or tendinomyalgia. However, every organ can be affected, leading to a very heterogeneous clinical picture. Currently, no effective systemic treatment is available for patients with Sjögren’s disease, despite the fact that many clinical trials have been performed in past years. These clinical trials were not able to show efficacy of the treatment compared to placebo.
In this thesis, we analysed commonly used outcome measures in Sjögren’s disease, such as measures for systemic disease activity (activity in various organs) and patient-reported symptoms, and we researched the application of these outcome measures in various types of research, both clinical trials as observational cohort studies. Because Sjögren’s disease is very heterogeneous, with many different symptoms which can differ per patient, we developed a composite endpoint to measure treatment effect in clinical trials, the Composite of Relevant Endpoints for Sjögren’s Syndrome (CRESS). The CRESS combines several different outcome measures. With the CRESS, we were able to show efficacy of the treatment compared to placebo, while previously, these trials were not able to show treatment effect. We believe these findings are an important step in finding effective treatment for patients with Sjögren’s disease.